Presently optical microscopes have been used for the visual measurement of the size of a chip and the size and position of a circuit pattern formed on the chip and the size of a wiring board and the size and position of the wiring pattern formed thereon. When measuring the size of a chip or a circuit pattern formed on the chip or the size of a wiring board or the size and position of the wiring pattern formed thereon by using an optical microscope, the moving stage of the optical microscope mounted with the chip or wiring board is operated to move the chip or wiring board so that an edge of the chip or wiring board or a contour of the circuit pattern or wiring pattern coincides with a thin vertical line formed in the field of the optical microscope, i.e., a marker. The position of the chip or wiring board is determined from the position of the moving stage when the marker is positioned as described. Such a measuring procedure is carried out repeatedly to determine the virtual positions of measuring points, and the distance between the measuring points and the relative positions between the objective portions are determined by calculation.
A measuring apparatus comprising an image signal detector and an image processor, and an inspecting apparatus disclosed in Japanese Patent Laid-open Patent Application (Kokai) No. 63-122229 have been proposed to carry out the foregoing measuring procedure automatically.
When measuring the chip or the circuit pattern formed on the chip, the wiring board or the wiring pattern formed on the wiring board through visual observation using an optical microscope, the contours of objective portions are recognized visually and the visual recognition of the contours need to be repeated by the number of times equal to that of the objective portions. Consequently, measurement using the above-described operation requires a lot of time, the measuring accuracy is dependent on the skill of the operator, and the measuring accuracy deteriorates with the progressive fatigue of the operator.
The conventional automatic measuring and inspecting apparatus for hybrid integrated circuit chips and patterns thereon operates using only one image signal detecting system among a bright field illumination system. Either a fluorescence detecting system, illustrated for example by U.S. Pat. Nos. 4,816,686 and 4,772,125, or a polarized light detecting system, illustrated for example by Japanese Laid-Open Patent Application Nos. 59-231402, 1-263540 and 2-71377. Thus, using such an illumination system further makes it difficult to form satisfactory images of all the objective portions of a circuit pattern formed on a hybrid integrated circuit chip provided with a hybrid integrated circuit by the conventional automatic measuring apparatus or the conventional inspecting apparatus.
Hybrid integrated circuit chips are chips having a ceramic base and an organic thin-film circuit pattern thereon. The thin-film circuit pattern may be in multiple layers. Such chips are used in the recently developed packaging technology known as controlled collapse chip connection (C4) and micro carrier for LSI chip (MCC). The C4 and MCC packaging technologies, illustrated for example in LSI Packaging Technology for Mainframe Computers, by K. Takeda, et al., IEICE Trans., vol. E74, No. 8, August 1991 and Micro Carrier for LSI Chip Used in the HITACM-880 Processor Group, by T. I. Morie, et al., Proceedings for 41st ECT Conference, May 1991, require the dimensions of the chip to be held to strict tolerances. Thus the measurement of the dimensions of the features of the chip are critical. Therefore, it is difficult to apply the conventional measuring apparatus to the measurement of the circuit pattern formed on the chip for forming a hybrid integrated circuit and obtain the level of accuracy needed for the above-described packaging technology.
Recently, the size of the wiring board and the density of elements formed on the wiring board have been progressively increased. When the wiring board is relatively large, measurement in a sufficiently high accuracy cannot be achieved by using a single image of the entire wiring board and a large amount of data needs to be processed. Therefore, the measuring apparatus must be provided with hardware of a large scale including an image storage device, which makes the measuring apparatus expensive and the measuring apparatus needs much time to process the image.